Status report of the Hard X-ray Detector
Shinya Yamada, RIKEN on behalf of the HXD team
The 4th Suzaku Conference 2011 @SLAC
2004
Wide-band Spectra of Suzaku
2
AXP 0142+61 (NS)
Cyg X-1 (BH)
Energy (keV)
10 1
0.1
0.01
1 10 100
GC
vFv
(from Max’s presen)
XIS (CCD) HXD-PIN HXD-GSO
Overview of Hard X-ray Detector (HXD)
3
HXD-PIN (64) 10~60 keV
HXD-GSO (16) 50~300 keV
HXD-WAM (20) Ohno’s talk
X-ray
Overview of Hard X-ray Detector (HXD)
4
W0 HXD-PIN (64) 10~60 keV
HXD-GSO (16) 50~300 keV
HXD-WAM (20) Ohno’s talk
Overview of Hard X-ray Detector (HXD)
5
HXD-PIN 10~60 keV
HXD-GSO 50~300 keV
HXD-WAM
W00
Overview of Hard X-ray Detector (HXD)
6
HXD-PIN 10~60 keV
HXD-GSO 50~300 keV
HXD-WAM
W00p0
Status of the HXD u Overview ~ all 116 sensors working well ~
u PIN (64 units) u taking measures for increase in thermal noise.
u GSO (16 units) u energy scale improved
u gain history updated u responses updated
u detailed analysis of Crab spectra (Kozu’s poster)
u BGO (16 units) u working properly.
u WAM(20) u working properly (Ohno’s talk)
7
Operations for HXD since June of 2009 u 2009, Sep. 13
u Count rate of HXD W01p3 suddenly flares up. u calmed down spontaneously.
u 2010, Jan. 16 u need to reduce FIFO-full and buffer flush in W3
u W3 PIN analog LD was increased. u PIN response epoch 7
u need to reduce buffer flush in W21p1 u in-orbit software LD was increased.
u 2010, Feb. 2 u need to reduce FIFO-full and buffer flush in W2
u W2 PIN analog LD was increased. u PIN response epoch 8
u 2010, Apr. 3 u need to reduce FIFO-full and buffer flush in W0
u W0 PIN analog LD was increased. u PIN response epoch 9
u 2010, Dec. 16 u LD cut in on-board DE (CPU) were increased for most of PIN.
u no effects for analysis
u 2011, May 25 u Need to reduce FIFO-full and buffer flush in W1 and W3
u W1 and W3 PIN analog LD was increased. u PIN response epoch 11
8
Calibration of HXD-PIN
Sho Nishino (Hiroshima U.)+, 2010, SPIE
9
Long-term count rates trend of 4 PINs in W32
10
Analog-LD ↓ was raised.
2005 2011
INPUT: Sho Nishino @Hiroshima U.
Long-term spectral variation of W22P2
11 15 keV 7.5 keV
Thermal noise increases with time.
Temperature-sorted spectra of W32P1
12 15 keV 7.5 keV
Higher temperature, larger thermal noise.
13
LD distribution for 64 PINs INPUT: Sho Nishino @Hiroshima U.
LD is increasing..
Gain & Energy resolution of 64 PINs
14
ΔE @Gd-K 43 keV
PI @Gd-K 43 keV
~ 2005
~ 2010
3.8 keV ~2005
4.7 keV ~ 2010
Gain shift << 1%
15
The Leakage Currents of PIN INPUT: Sho Nishino @Hiroshima U.
Sugizaki+97’ Sugiho Master thesis
Mostly electronics unchanged
Leak current
ΔE increases explained by increase of leak current.
Calibration of HXD-GSO
Yamada, Makishima+, 2011, PASJ
16
Before calibration…
17
Kokubun+ 2007
A single powelaw fit… something wrong but what? We’d been struggling for studying its cause for more then 2 years since the launch….
The Background Spectrum of HXD-GSO
18
e+e- 511 keV
α decay natural 152Gd ~ 350 keV
IC 151m Eu ~ 200 keV?
EC 153Gd ~ 150 keV?
EC 151Gd ~ 70 keV?
Kokubun+ 2007
(1) The non-linear effect of light yields in GSO
19 19
e - response (Uchiyama 1998)
Photon response (Kitaguchi 2006)
Annihilation line à Single γ 511 keV Activation lines à Multiple γ , e -
“70 keV” lowered by ~6 %, “150 keV” by ~ 5%, “196 keV” by ~ 3 %
151Gd 20 keV
151Eu
EC Ex). 70 keV
Eu K binding E ~ 50 keV γ decay
Several e- or γ reduces light yeilds, considering all decay probability, The correct energy are,
Fluorescence or Auger e-
gamma-ray or IC e-
E vs. light yeilds relation in GSO
Num
ber o
f Wel
l uni
ts
ADC channel70 80 90
0
2
4
6
8
(2) The Analog Offset (so-called pedestal) Shift
20
Laboratory Power June, 2004
Satellite Power, Aug. 2004
Satellite Power Aug. 2006 (In orbit)
After using the satellite power, the analog offset changed by ~ 8 ch lower cf. 8 ch << 4096 ch (the maximum ADC channels of GSO)
pedestal
Agreement with On-Ground measurements
21 100 200 300 500500.9
1.0
1.0
1.1
1.0
1.1
1000
2000
200
500
1.1
Ratio
Ratio
Ratio
H - !
H (A
DC ch
anne
l)
Q (channel)
on ground
(1) inc. light yeild
(2) inc. analog offset Energy (keV)
GSO
bra
nch
wid
th (k
eV)
30 50 200100 500
2
5
10
in orbit (new) on ground
simulation
in orbit (old)
In-orbit data agrees with both simulation and on-ground data. (Yamada, Makishima+11, PASJ)
in orbit (old)
Input charge vs. ADC plot
Both agrees.
Improvement on reproducing gain history
22
The remote pass from SAA The 1st SAA pass The 5th SAA pass
Gain recovery depending on the order of SAA pass will enable us to improve a modeling of gain history.
1 orbit
(~15 orbits/day)
Crab Nebula
Kozu’s poster, and her paper is in progress.
23
10 3
0.01
0.1
1
norm
aliz
ed c
ount
s s
keV
10020 50 2000.5
1
1.5
ratio
Energy (keV)
HXD Spectra of the Crab Nebula
24 Kouzu’s poster
Now that the best-fit parameters with broken powerwlaw Γ1 ~ 2.08-2.12, Eb ~ 110-160, Γ2 ~ 2.2-2.3
Ratio
Counts/ s/keV
500
The ratio to a single powerlaw with Γ = 2.1
Long-term HXD flux trend of the Crab Nebula
25
HXD
12-50 keV (erg/s/cm2)
50-100 keV (erg/s/cm2)
100-500 keV (cnt/s stat&sys err)
2005 2010
(Kouzu’s poster)
Aug 27, 2008
Energy (keV)
cnt/s
/cm
2 /keV
20 50 100 500
1
10-2
10-4
1 0.5
1.5
ratio
Ratio to best fit power law
Aug 27, 2008
Energy (keV)
cnt/s
/cm
2 /keV
20 50 100 500
1
10-2
10-4
1 0.5
1.5
ratio
Ratio to best fit power law
The HXD fluxes follows with those of other missions.
Long-term spectral change of Crab Nelula
26
1.5
1.0
20 50 100 200
Energy (keV)
ratio
(Aug. 08: Bright) / (Feb. 10:Dim)
0.5
500
PIN GSO
Best fit constant
More significant change in higher energy E > 200 keV
(Kouzu’s poster)
Summary
u HXD on board Suzaku has realized the wide-band and high-quality observation without any problems.
u Adequate operation for LD of HXD-PIN have been performed, so that all units can be properly analyzed.
u The new HXD-GSO energy scale are obtained by utilizing the calculation of light yield and the shift of an analog offset. Corresponding responses and software have been released.
u Now that we can quantify not only the detailed shape of the Crab Nebula, but also its variation with time.
27
28
Thank you (photo; 2004/04/30 HXD completed)
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29
Wide-Band Spectra of Suzaku XIS (CCD) HXD-PIN HXD-GSO
Cra
b R
atio
Ada+ (2008)
Response Simulator includes Light yields
30
Incident X-ray into HXD
Calculate E deposited in HXD
Accumulate deposited E ≠ Light Yield
SimHXD : Framework of Response Generator ( Terada et al. 2005 )
Calculate E of secondary e- or γ in GSO
Convert each E into light yield by using E vs. LY. relation in GSO
Accumulate Light Yields
New GSO response have been released since April of 2010
new previous
Geant 4 ANL